work on session length helper
helperish thing to publish metrics on time spent in sessions per MNO
remove commented code & update docstring
include SessionLengthHelper in Gruntfile tests
fix missing var (thanks @justinvdm)
more tests
grow support for an attach() method (thanks @justinvdm)
have firing of metrics also register in attach
include in grunt file & generated output
no longer require explicit markers (thanks @justinvdm)
attach to the `go.` object
avoid leaking variables (thanks @justinvdm)
wrap the whole thing
include vars in module
new builds
Merge branch 'feature/issue-131-graph-session-time' into develop